Methods and apparatuses for conducting solid-liquid-vapor multiple phase transformation operations

摘要

The invention is a method with equipments for conducting the solid-liquid-vapor multiple phase transformation steps of processes such as vacuum freezing, wet distillative freezing, vacuum crystallization and primary refrigerant eutectic freezing. All these processes require simultaneous vaporization and crystallization. The invented method for conducting this common step consists of (1) distributing the solution over a rotating surface area to form liquid films (2) subjecting the liquid films to simultaneous vaporization and crystallization (3) removing the crystals from the surfaces and (4) transporting the crystals to the next processing zone. The surfaces can be rotating screws with intermeshing flights or a sets of disks on rotating shafts. The screws are partially submerged in the solution. Elements of the screws are wetted when they are rotated into the pool. Vaporization and crystallization occur when the screw elements are rotated out of the pool because the vessel is maintained at a pressure below the multiple phase-that is solid-liquid-vapor-equilibrium pressure of the solution. The crystals either dislodge from the elements when the elements re-enter the pool or they build up to a certain thickness and are then rubbed off by the crystal buildup on the intermeshing screw. Whether the crystals float or sink, they are conveyed by the screws to the next processing zone. Disk arrangements can be used just like the screws. However, a separate conveying screw is needed to transport the crystals.